Hydrocarbon conversion process



HYDROCARBON CONVERSION PROCESS Grady L. Payne, Mickleton, N. J.,assignor to Socony Mobil Oil Company, Inc., a corporation of New YorkApplication January 4, H52, Serial No. 264,951

16 Claims. (Cl. 196-1411) This invention relates to a process forcracking hydrocarbon oils and particularly is directed to a method fortreatment of the charge oil prior to conversion to improve the crackingcharacteristics thereof. More specifically, the present invention isconcerned with the extraction of an aromatic-containing cracking chargestock with the extract phase resulting from previous treatment of apetroleum lubricating oil with a solvent having a preferentialselectivity for the relatively more aromatic type constituents ascompared with the more paraffinic type constituents and subsequentsubjection of the rafiinate obtained from said extraction to catalyticcracking.

It has heretofore been known that oils having a relatively high contentof aromatic hydrocarbons are less suitable for cracking thannon-aromatic oils since cracking of aromatic-containing oils results ina greater degradation of the oil into undesired products such as cokeand gas for a given conversion to gasoline than cracking of non-aromaticoils. Thus, the ratio of gasoline to coke or gas for a given conversionis higher when cracking nonaromatic oils than when cracking aromaticoils. In view of the foregoing, it has been proposed to remove aromaticconstituents from aromatic charge oil before subjecting the same tocracking. Removal of aromatic constituents may be accomplished bytreatment of the cracking charge stock with a solvent having a selectivesolvent power for aromatics as compared with non-aromatics. Suchproposed treatment, however, has been relatively expensive due to thenecessity for recovering solvent and accordingly has not been practicedin commercial operation since the improved cracking characteristics ofthe stock so treated have ordinarily not offset the additionaloperational costs involved.

It has also been known, prior to the present invention, to improve thequalities of petroleum lubricating oil fractions by extraction with asolvent having a preferential selectivity for the relatively morearomatic type constituents as compared to the relatively more parafiinictype constituents. In such prior practice, the usual procedure forsolvent refining of lubricating oils has been to contact the oil stockundergoing treatment with solvent in an extraction tower. Thus, the oilcharge is ordinarily introduced into the lower portion of an elongatedtower while solvent is introduced into the upper portion thereof. Theoil and solvent move counter-currently through the tower,

'efiicient contact between the counter-currently moving phases beinggenerally secured by suitable distributing and contacting means, such asby contact masses, distributing plates, pierced plates, and the like.Temperature and pressure conditions are maintained in the tower tosecure the formation of extract and rafiinate phases. The resultingextract phase containing the major portion of the solvent, together withextracted material removed from the oil, accumulates in the bottom ofthe tower. The rafiinate phase, comprising solvent insolubleconstituents of the oil mixed with a small proportion of the solvent,accumulates in the upper portion of the tower. The respective phases aresegregated and removed from the tower, after which the solvent isremoved by separately distilling these phases, driving the solventtherefrom as 2,748,055 Patented May 29, 1956 LI overhead. The solvent soremoved is thereafter condensed and recycled for further treatment ofadditional charge oil.

In accordance with the present invention, the extract phase resultingfrom refining a lubricating oil fraction with a solvent having apreferential selectivity for the relatively more aromatic typeconstituents as compared with the relatively more parafiinic typeconstituents is employed directly without distillation in extraction ofa petroleum oil to be used as cracking charge stock. The extract andraflinate fractions obtained from said extraction are thereafterseparated and the solvent is removed therefrom. The resulting rallinatefraction is then subjected to catalytic cracking, affording a high yieldof product characterized by an improved gasoline/ coke ratio. Thepresent method affords a combined solvent extraction procedure fortreatment of petroleum lubricating oil fractions and refining processfor oils to be used as cracking charge stocks with the elimination ofthe time-consuming and expensive distillation step heretofore employedin effecting separation of the extract phase resulting from solventrefining of lubricating oils. Ithas further been unexpectedly found inpractice of the process of this invention that aromatic-containingcracking charge stocks treated with the extract phase of a solventrefined lubricating oil is advantageous since an exchange is therebyefiected between paraffinic material in the extract phasefromluhricating oil refining and aromatics in the cracking charges took.Such exchange has been'found'to resents an improved yield of crackingcharge oil raflinate over that obtained in the extraction of such oilwherein the solvent is used directly.

The extracts resulting from treatment of petroleum lubricating oils withany of the solvents having a preferential "selectivity for therelatively more aromatic type constituents as compared to the relativelymore parafiinic type constituents may be employed in the presentprocess. Solvents of this class are, for example, furfural, sulfurdioxide, phenol, cresol, aniline, nitrobenzene, betabetadichloroethylether (chlorex) and the like. Suchsolvents may have been furthermodified with regard to selectivity and solvent power by the addition ofinert solvents as, for example, by the addition of water, alcohols, orglycols. Of these solvents, preference'is accorded furfural and mixturesthereof. The method of the invention may be practiced in any manner inwhich contact between the respective oil charges and solvent or solventmixtures is maintained and the ratfinate resulting from extraction ofthe cracking charge oil may be subjected to catalytic cracking under theusual conditions employed in such operations.

Reference will now be made to the accompanying drawing in order tofurther describe the invention.

In the drawing, lubricating oil is introduced through line 10 and thesolvent used for extraction is introduced through line 11. Theextraction is carried out in solvent extraction step 12 by any suitablemeans. The resulting lubricating oil ratfinate is passed through line 13to solvent recovery step 14. The recovered solvent passes through line15 and is recycled through line 16 for use in further extraction. Theremaining lube oil raffinate, free of solvent, passes through line 17.The lubricating oil extract'is removed through line 18 to solventextraction step 19, wherein it is contacted with cracking charge oilintroduced through line 20. The resulting cracking charge oil rafiinateis withdrawn through line 21 and conducted to a solvent recovery step22. Solvent recovered in such step passes through line 23 and isrecycled through line 16 tothe original solvent extraction step. Theremaining charge oil ratiinate, stripped of solvent, is withdrawnthrough line 24 and passed to catalytic cracking step 25.

The resulting gaseous products may be removed through line 26 to asuitable gas recovery system not shown. The gasoline may be removed tostorage or subsequent refining through line 27. Recycle stock boilingabove the gasoline range may be removed through line 28 and conducted tostorage or all or a portion of such recycle stock may be conductedthrough line 29 and recycled to solvent extraction step 19. The chargeoil extract is withdrawn through line 30 and conducted to solventrecovery step 31. The recovered solvent is removed through line 32 andrecycled to solvent extraction step 12. The remaining stripped extractsare withdrawn through line 33.

The combined solvent refining and catalytic cracking process of thisinvention may be carried out either as a continuous operation or on abatch or semi-batch basis wherein the solvent lubricating oil extractfrom a previous refining step may be introduced from a suitable storagesource to contact with the cracking charge oil undergoing treatment.

It is contemplated that the solvent extract of lubricating oil utilizedherein as a treating medium is that obtained by the usual solventextraction of petroleum lubricating oil stocks under conventionalcontacting conditions, that is, the contacting of a petroleumlubricating oil fraction characterized by an A. P. I. gravity of betweenabout and about 40 with a solvent at a temperature of between about 80F. and about 300 F., the volume ratio of solvent to oil being maintainedbetween about 0.5 and about 10.0.

The cracking charge stock treated in accordance with this invention maybe any of the aromatic-containing stocks heretofore employed and maycontain both straight run and cracked products or a mixture of the two.Typical of the charge stocks treated are distillate fuel oils andcatalytic cracking cycle stocks. Generally, the cracking charge oilstreated by the present process are characterized by a viscosity (S. U.V. at 122 F.) of between about 35 and about 200 seconds and boilingwithin the approximate range of 3501000 F. The charge stock treated bythe method described herein further generally contains at least about 25per cent by weight of aromatic type constituents.

The term petroleum lubricating oil as used herein is in accordance withthe usual significance accorded that designation and includes all thedistillate obtained from the crude oil after gas oil has been expelledas well as some of the residues that are left in the still whennonasphaltie crude oils are distilled. Generally, lubricating oilfractions refined in accordance with the instant process arecharacterized by a viscosity (S. U. V. at 210 F.) of between about 35and about 200 seconds.

The cracking of the rafiinate obtained upon extraction of the charge oilwith the lubricating oil extract phase is carried out under conventionalcatalytic cracking conditions. Thus, the temperatures employed arewithin the approximate range of 800 to 1200 F. and the pressures areonly such as are suflicient to cause the oil vapors to pass through thevarious steps of the process. Any cracking catalyst which has been foundsuitable for the conversion of high boiling hydrocarbons into thegasoline distillate range may be satisfactorily used. This includescatalysts of both natural and synthetic origin such as the various claysand other natural earths which have been treated with acids or otherchemical methods and the synthetic catalysts prepared from silica andvarious refractory oxides, for example, gel composites of si1icaalumina,silica-zirconia, silica-alumina-chromia, silicaalumina-zirconia,silica-alumina-thoria, and the like. These catalysts may be treated andprepared by any of various well known procedures.

The procedure of this invention accordingly involves use of the extractphase from a solvent lubricating oil refining operation to extractcracking charge oils and subsequent subjection of the rafiinate soobtained to catalytic cracking. The contacting of solvent lubricatingoil extract and cracking charge oil is generally accomplished at atemperature between about 60 F. and about 200 F. under conditions togive the equivalent of from 0.5 to 10 theoretical counter-currentextraction stages. The volume ratio of solvent lubricating oil extractto cracking charge oil is generally between about 0.1 and about 10. Thesolvent lubricating oil extract, for example, the extract resulting upontreating a lubricating oil with furfural ordinarily contains 70 to percent of the total furfural employed in lubricating oil extraction. Thisextract may, in accordance with the procedure of this invention, be useddirectly for extraction of cracking charge oils or, alternatively, thelubricating oil extract may be cooled to a temperature such that extractoil separates therefrom and the remaining solvent-enriched phase may beemployed to treat cracking charge oil. The solvent power of thelubricating oil extract may also be adjusted by cooling and saturatingwith water and decanting the oil phase, which separates before chargingto the cracking charge oil treating step. The extract phase resultingfrom such treatment of cracking charge oils thus contains the extractedcomponents of both lubricating oil and cracking charge oil, which arerecovered together in a single solvent stripping operation. It willaccordingly be seen that although the rafiinate must be strippedseparately from both the lubricating oil and the cracking charge oil,one of the two major extract stripping operations in the overall processis eliminated, namely, the stripping of the extract phase from solventrefining of the lubricating oil. Since solvent recovery represents themajor processing cost of a solvent refining operation, the processingprocedure described herein provides an inexpensive improved refiningmethod for the treatment of aromatic-containing cracking charge oils.

In addition, it has been found that there is a distinct and unexpectedadvantage in using the solvent extract phase from a lubricating oiloperation for extraction of a cracking charge oil since an exchange ofparaffins in the extract phase with aromatics in the cracking charge oilis effected during contact. This exchange of aromatics for heavierparaffins is definitely advantageous as it pro vides an increased yieldof good cracking stock to offset the loss of aromatics which are poor incracking characteristics. Thus, the process described herein enablesimprovement in the yields of gasoline which can be obtained by catalyticcracking. In addition, the amounts of carbon deposition on the crackingcatalyst are decreased so that the time of processing, particularly inregeneration of the catalyst, is materially decreased. Since theconversion of cracking charge oil to gasoline is also increased, theeffect is to increase plant capacity for a given size of equipment.

The following comparative examples will serve to illustrate theimprovements realized in accordance with the method of this invention.The cracking charge oil employed in Examples 1 to 3 was a distillatefuel oil stock having a boiling point of 450 to 900 F. and an A. P. I.gravity of about 20.5. The solvents used in these examples were furfuraland the extract phase from a previous furfural refined lubricating oilstock. Individual samples of the fuel oil were contacted with freshfurfural and with the extract phase from a furfural refined lubricatingoil stock. This extract phase contained approximately 74.5% by volume offurfural and 25.5% by volume of extracted lubricating oil components of10 A. P. I. gravity. Such extract was obtained by contacting alubricating oil boiling in the range of 425 to 950 F. with furfural at atemperature between about 160 and about 230 F., the volume ratio offurfural to lubricating oil being about 1.75. The extract phase used inthe present evaluation was saturated with furfural at F.

The raffinate phases resulting from furfural treatment of the distillatefuel oil and treatment of said fuel oil with the furfural lubricatingoil extract were evaluated as cracking charge stocks in the presence ofa silica-alu- 5 mina cracking catalyst employing the TCC techniqueoperating under the following conditions:

Space velocity, v./hr./v 0.86 Catalyst-to-oil ratio, vol 1.5Temperature, F 880 Steam, per cent wt cycle stock having a boiling pointrange of 450 to 850 F. and an A. P. "I. gravity of about 17 wasemployed. The solvent employed was the extract phase resulting fromfurfural refining of a lubricating oil stock. Such extract was obtainedby contacting a lubricating oil boiling in a range of 6 00 to 900 F.with furt'ural at a temperature between about 150 and about 250 F., thevolume ratio of furfural to lubricating oil being about 1.5. In Example4, the catalytic recycle stock extracted with 50% by volume of thelubricating oil extract phase at It will be noted from the foregoingresults that the Y extract phase from furfural refining of lubricatingoil is an efiective solvent medium for the treatment of a distillatefuel oil stock. Thus, distillate fuel oil gives a gasoline/coke ratio,upon cracking, of 2.6; the fuel oil Table I Example Number 1 2 3 ExtractPhase from Fur- Solvent None fural Treatment of Wgter Lubricating OilSat- 0 urated at 100 F.

Solvent-to-Oil Ratio, Vol 0.33 0. 50 2.00 Temperature, "F 100 100 100Raflinate:

Yield, Percent Vol. 'ICC Heavy Fuel Oil 77. 4 73. 2 87. 8 ExtractGravity, Specific 1.1201 1. 0823 1. 0803 Extract Viscosity, KV at 100 F150 11 183 TCC Evaluation Charge Stock Raw Stock Raffinate RaffinateRafiinate Properties:

Gravity, A1I 20. 5 27. 3 30. 3 28. 2

Aniline Point, "F 169 191 193 180 Yields, based on TCC Charge:

C4 Free Motor Gasoline, Percent Vol 21.0 29. 1 30. 0 31. 3

Cycle Stock, Percent Vol. 60. 7 52. 6 52. 6 54. 3

Total C4S 9. 2 13. 0 13. 7 12.6

03 Free Liquid Recovery, Percent Wt 90. 9 94. 7 96. 3 98. 2

Dry Gas, Percent Wt 7. 6 8. 1 7. 8 7. 0

Coke, Percent Wt 8.1 5. 2 4. 4 3. 4

Gasoline/Coke Ratio 2. 6 5. 6 6. 8 9. 2

110 F. resulted in a ratfinate yield increase of 65.3%, an increase inA. P. I. gravity of from 168 to 27.4, and an increase in diesel indexfrom 24 to 51. Upon cracking this raflinate, a 30.1% vvolume yield ofgasoline and a 4.3% weight yield of coke was obtained comtreated withfresh furfural, :a ratio of 5.6; and a fuel oil 4(- pared with a 19%volume yield of gasoline and an 8.8% treated with the extract phase froma previous furfural gh yi of coke h untreated recycle stockrefinedlubricating oil, a ratio in the range of 6.8 to 9.2. Example 5 ShOfVSthat extracting the Catalytic Cracking AS will be noted there is a fu thr advantage n recycle stock with 150% by volume of the lubricating oil,ployment of the furfurai extract phase from lubricating extract i P 795%y Volumf oil operations due to an exchange of paraflinic material fi gyleld' graYlty of thls Pmduct was in the extract phase from lubricatingoil refining with 3 5 z W cracked aromatic material in the fuel oil,resulting in an imb a? 2 1:: f .3? i g and proved yield of about 88%based on fuel oil. y g y p 0V1 ng Improve economlgs E l 4 t 6 s mmarizedin Table II set forth over the use of the extract phase to cycle stockratio XaIIlP e5 0 th b1 f th employed 1n Example 4. Example 6 shows thatby below, dem e a 0 6 Present Process o employing 300% by volumelubricating oil extract at de'afom'atlze Y recycle stock as shqwn F., araflinate yield of 104.8% by volume was oby the lncleastfs 111 dleselIndex. gl'avltytained. This'material had a 265 A. P. I. gravity and Theconcentration of the aromatics 1n the extracted hya di l i d f 49, U kih rafii t drocarbon phases is shown by the decreases in mixed an1- Fduced 35.2% by volume gasoline and 4.8% by weight line points. In theseexamples, a catalytic cracking recoke. The foregoing results aresummarized below:

Table II Example No 4 5 6 Extraction:

Fnrfural Extract Phase Dosage, Percent Vol. of 50 300 Catalytic RecycleStock Extraction Temp., F. 110 110 110 Catalytic Rseztgclge RafiinateExtract Rafiiuate Extract Rafifinate Extract Yields, Percent Vol.1

Raflinate (Paratfinic) 100- 0 65. 3 79. 5 104. 8 Extract (Aromatic)Inspections:

Gravity, API Sp. Gr.@60F Aniline Pt.. F MixedAnil' ePt.,F- Diesel IndexCatalytic Cracking:

Gasoline Yield, Percent Vol Coke, Percent Wt In Examples 7, 8, and 9,comparative runs were made employing the extract phases resulting fromsolvent refining of a petroleum lubricating oil with furfural, phenol,and chlorex, respectively. The charge stock employed in these exampleswas a catalytic cracking synthetic tower bottoms having a boiling pointrange of 450 to 870 F. and an A. P. I. gravity of about 20.5 Individualsamples of the charge stock were contacted with the extract phase from asolvent refined lubricating oil stock wherein furfural, phenol, andchlorex had been employed as the treating solvents. Such extractresulted from contacting a lubricating oil boiling in the range of 450to 800 F. with the appropriate solvent at a temperature between about 80and about 260 F., the volume ratio of solvent to lubricating oil beingabout 2 to 3.5.

The conditions of extraction and the properties of the resultingraflinate and extract phases, together with the Cat-A cracking resultsobtained upon cracking the rafiinate in each instance, are set forth inTable III below:

Table III catalytic cracking synthetic tower bottoms having a boilingrange of 450 to 870 F. and an A. P. I. gravity of about 20.7 wasextracted in a three-stage counter-current operation at temperatures of100 to 110 F. Raffinates were evaluated for cracking characteristics bymeans of Cat-A type (liquid feed at 850 F.) test. In Example 10, thecharge stock was extracted with aqueous furfural solvent. In Example 11,the solvent employed was the extract phase resulting from contact of alubricating oil boiling in the range of 450 to 850 F. with furfural at atemperature between about 225 and about 275 F., the volume ratio offurfural to lubricating oil being about 3.5. In Example 12, the solventwas the extract phase resulting from contacting a lubricating oilboiling in the range of 450 to 850 F. with furfural at a temperaturebetween about 150 to about 225 F., the volume ratio of furfural tolubricating oil being about 2. In Example 13, the solvent was theextract phase resulting from contact of Charge Stock Catalytic CrackingSynthetic Tower Bottoms Selective Solv Furtnral Phenol Chlorex ExtractPhase Composition, Percent Vol.:

Oil 17 13 I7 Selective Solvent 83 87 83 Extraction Conditions (3 Stage):

Extract Phase, Percent Vol 300 200 200 Temperature, F 100 130 80Untreated igggg Rafiinate Extract Ratrlnate Extract Raifinate ExtractBottoms Treating Yield, Percent Vol Inspections:

Gravity, API Gravity, Specific-.- Aniline Point, F Mixed Aniline Pt "FSUV 122 F. Cat A Cracking Results:

Gas, Percent Wt Gasoline, 410 F. EP, Percent Vol Coke, Percent WtGasoline/Coke, Vol/Wt The results obtained upon cracking the raffinatesshow improvement in gasoline yield and decrease in coke. As will benoted, these results were substantially the same upon crackingraffinates obtained by treating the synthetic tower bottoms withfurfural, phenol, or chlorex extract resulting from previous refining ofa lubricating oil.

In Examples 10 to 13, a charge stock consisting of a a lubricating oilboiling in the range of 700 to 1000 F. with furfural at a temperaturebetween about 225 and about 275 F., the volume ratio of furfural tolubricating oil being about 3. The results obtained by refining the 5synthetic tower bottoms with the above lubricating oil extract phasesand the results obtained upon cracking of the raflinate are summarizedin Table IV.

Table IV Example No Extraction:

Charge Stock Catalytic Cracking Synthetic Tower Bottoms Solvent Solvent,Percent Vol. of Charge....

Rafiinate Yield, Percent Vol. Chg

Cat A Cracking of Raftinate Yields, Based on Chg. to Cracking:

Gasoline, 410 F. EP, Percent Vol 20. 7

Coke, Percent Wt 9. 6

Gasoline/Coke Ratio 2.2 Yields, Based on Chg. to Extraction:

Gasoline, 410 F. EP, Percept Vol 20. 7

1 Contains 4% vol. water.

It will be evident from the above data that extraction of the synthetic.tower bottoms charge with practical dosages of the lubricating oilextract phases as solvent results in the production of raflinates withyields of the order of 100 to 120% based on the synthetic tower bottomscharge as compared with a yield of only 77% for extraction with freshfurfural. It is further to be noted that the solvent to oil ratioemployed in the case of furfural represents the lowest operable ratiofor producing the highest quantity of rafiinate. The distinctimprovement in rafiinate yield is possible because of the presence ofparaffins in the lubricating oil extract phase, some of which aretransferred to the rafiinate phase when the lubricating oil extractphase employed as solvent is contacted with the synthetic tower bottomscharge stock. It will further be seen from the results of Table IV thatthe raflinates resulting from treatment with lubricating oil extractyield 50 to 100% more gasoline in cracking than the untreated materialand 20 to 40% more than the raifinate produced by refining with furturalalone.

The effect of variations in dosage of lubricating oil extract employedas solvent on the yields and cracking characteristics of a catalyticcracking synthetic tower bottoms charge are shown in Examples 14, 15,and 16, of Table V. The charge stock employed in these examples was acatalytic cracking synthetic tower bottoms having a boiling range ofabout 450 to about 850 F. and an A. P. I. gravity of about 17. Thelubricating oil extract employed as solvent was that obtained fromfurfural refining of a lubricating oil boiling in the range of 600 to900 F. with furfural at a temperature between about 150 and about 250F., the volume ratio of furfural to lubricating oil being about 1.5.Extractions were performed in a three-stage counter-current operation ata temperature of 100 F. Raffinates were evaluated for crackingcharacteristics by means of Cat-A type (liquid feed at 850 F.) test.

range of about 350 to about 1000 F. with the extract phase resultingfrom the refining of a petroleum lubricating oil having a SayboltUniversal viscosity at 210 F. of about to about 200 seconds with asolvent selected from the class of solvents which have a preferentialselectivity for the relatively more aromatic type constituents ascompared to the relatively more paraffinic type constituents, separatingthe resulting extract and rafiinate fractions, removing solvent fromsaid separated raflinate fraction and subjecting the resulting rafiinatefraction, freed of solvent, to catalytic cracking.

2. A hydrocarbon conversion process which comprises extracting anaromatic-containing cracking charge hydrocarbon stock having a SayboltUniversal viscosity at 122 F. of about 35 to about 200 seconds andhaving a boiling range of about 350 to about 1000 F. into an in-.soluble ralfinate fraction and a soluble extract fraction with theextract phase from a previous solvent refined petroleum lubricating oilhaving a Saybolt Universal viscosity at 210 F. of about 35 to about 200seconds treated with a solvent selected from the class of solvents whichhave a preferential selectivity for the relatively more aromatic typeconstituents as compared to the relatively more paraflinic typeconstituents, separating said rafiinate fraction from said extractfraction, distilling solvent from said separated raffinate fraction andsubjecting the resulting rafiinate to catalytic cracking.

3. A hydrocarbon conversion process which comprises contacting anaromatic-containing cracking charge hydrocarbon stock having a SayboltUniversal viscosity at 122 F. of about 35 to about 200 seconds andhaving a boiling range of about 350 to about 1000 F. with the extractphase resulting from previous refining of a petroleum lubricating oilhaving a Saybolt Universal viscosity at 210 F. of about 35 to about 200seconds with a solvent selected from the class of solvents which have apreferential selectivity for the relatively more aromatic Table VExample No 14 15 16 Extraction:

Charge Stock Catalytic Cracking Synthetic Tower Bottoms SolventLubricating Oil, Lubricating Oil, Lubricating Oil,

Extract Phase. Extract Phase. Extract Phase. Solvent, Percent Vol. ofCharge... 150 300.

, Rafiinate Yield, Percent Vol. Chg.. 100.0 65.3 79.5 104.8. Cat A"Cracking of Raflinate Yields,

Based on Chg. to Cracking:

Gasoline, 410 F. EP, Percent Vol 19. 0 30.1. 34.3.- 35.2. Coke, PercentWt 8.8 4.3.. 4.6.. 4.8. Gasoline/Coke Ratio 2. 2 7.0. 7.5.. 7.3. Yields,Based on Chg. to Extraction:

Gasoline, 410 F. EP, Percent V0l... 19.0 19.6... 27.3.- 36.9.

It will be observed that in cracking the raffinate produced at the lowerextract phase discharge (50%), the gasoline yield was appreciably higherand the coke yield appreciably lower than for the untreated material.However, the higher gasoline yield is offset by the treating lossincurred in the extraction. On the other hand, when extract phase dosagewas increased to ISO-300%, the extraction yields were increased markedlyand at the same time the yield of gasoline obtainable by cracking theraifinates increased with a concurrent slight increase in coke yield.The combined eifect of these two factors was a 50-100% increase ingasoline production and an over-all reduction in coke lay-down obtainedby extracting the synthetic tower bottoms and cracking the raflinate ascompared to cracking the untreated material.

I claim:

1. A hydrocarbon conversion process which comprises contacting anaromatic-containing cracking charge hydrocarbon stock having a SayboltUniversal viscosity at 122 F. of about 35 to about 200 seconds andhaving a boiling type constituents as compared to the relatively moreparafiinic type constituents, separating the resulting extract fractionand raflinate fraction, removing solvent from said separated rafiinatefraction, subjecting the solvent-free raffinate fraction to catalyticcracking, recovering gaseous products, gasoline, and oil boiling higherthan gasoline and recycling said higher boiling oil to contact with theaforesaid extract phase.

4. A process for converting hydrocarbons and refining petroleumlubricating oils, which comprises extracting a petroleum lubricating oilboiling within the range of about 425 to about 1000 F. and having aSaybolt Universal viscosity at 210 F. of about 35 to about 200 secondswith a solvent having a preferential selectivity for the relatively morearomatic type constituents as compared to the relatively more parafiinictype constituents into an insoluble rafiinate fraction and an extractfraction dissolved in said solvent, separating said extract fractionfrom said raflinate fraction, removing solvent from said separatedraflinate fraction, returning said solvent to further contact with saidlubricating oil, directly contacting said separated extract fractionwith an aromatic-containing cracking charge hydrocarbon stock having aSayboltUniversal viscosity at 122 F. of about 35 to about 200 seconds,separating the resulting immiscible extract and raffinate phases whichform, removing solvent from eachof said separated phases, returning thesolvent so recovered to further contact with said lubricating oil, andsubjecting the raflinate phase, freed of solvent, to catalytic cracking.

5. An improved process for conversion of a catalytic cracking recyclestock having a Saybolt Universal viscosity at 122 F. of about 35 toabout 20.0 seconds, a boiling range of about 350 to about 1000" F. andcontaining at least about 25 per cent of aromatic-type constituents,which comprises contacting the same with the extract phaseresulting fromthe refining of a petroleum lubricating oil having a Saybolt Universalviscosity at 210 F. of about 35 to about 200 seconds, with a solventselected from the class of solvents which have a preferentialselectivity vfor the relatively more aromatic type constituents ascompared to the relatively more parafiinic type constituents, separatingthe resulting extract and raffinate fractions, removing solvent fromsaid separate raffinate fraction and subjecting the resulting raflinatefraction, freed of solvent, to catalytic cracking.

6. A process for simultaneously converting hydrocarbons and refiningpetroleum lubricating oils, which comprises extracting a petroleumlubricating oil having a Saybolt Universal viscosity at 210 F. of about35 to about 200 seconds with a solvent having a preferential selectivityfor the relatively more aromatic type constituents as compared to therelatively more paraffinic type constituents into an insoluble rafiinatefraction and an extract fraction dissolved in said solvent, separatingsaid extract fraction from said raflinate fraction, removing solventfrom said separated rafiinate fraction, returning said solvent tofurther contact with said lubricating oil, directly contacting saidseparated extract fraction with an aromatic-containing cracking chargehydrocarbon stock having a Saybolt Universal viscosity at 122 F. ofabout 35 to about 200 seconds and having a boiling range of about 350 toabout 1000 F. and having a major portion thereof boiling in the boilingrange of the aforesaid lubricating oil, separating the resultingimmiscible extract and rafiinate phases which form, removing solventfrom each of said separated phases, returning the solvent so recoveredto further contact with said lubricating oil, subjecting the raffinatephase, freed of solvent, to catalytic cracking, recovering gaseousproducts, gasoline, and oil boiling higher than gasoline and recyclingsaid higher boiling oil to contact with the aforesaid extract fraction.

7. A hydrocarbon conversion process which comprises extracting anaromatic-containing cracking charge hydrocarbon stock having a SayboltUniversal viscosity at 122 F. of about 35 to about 200 seconds and aboiling range of about 350 to about 1000 F. into an insoluble railinatefraction and a soluble extract fraction with the extract phase from aprevious furfural refined petroleum lubricating oil having a SayboltUniversal viscosity at 210 F. of about 35 to about 200 seconds,separating said raftinate fraction from said extract fraction,distilling furfural from said separated raffinate fraction andsubjecting the ra'fiinate, freed of furfural, to catalytic cracking.

8. A hydrocarbon conversion process which comprises extracting anaromatic-containing cracking charge hydrocarbon stock having a SayboltUniversal viscosity at 122 F. of about 35 to about 200 seconds andhaving a boiling range of about 350 to about 1000 F. and containing atleast about 25 per cent aromatic-type constituents into an insolubleraffinate fraction and a soluble extract fraction with the extract phasefrom a petroleum lubricating oil having a Saybolt Universal viscosityat'210 F. of about 35 to about 200 seconds previously refined withphenol, separating said raffinate fraction from said extract fraction,distilling phenol from said separated raffinate frac- 3?. tion andsubjecting the raffinate, freed of phenol, to catalytic cracking.

9. A hydrocarbon conversion process which comprises extracting anaromatic-containing cracking charge hydrocarbon stock having a SayboltUniversal viscosity atl22 F. of about 35 to about 200 seconds and havinga boiling range of about 350 to about 1000 F. into an insolubleraifinate fraction and a soluble extract fraction with the extract phasefrom a petroleum lubricating oil having a Saybolt Universal viscosity at210 F. of about 35 to about 200 seconds previously solvent refined withbeta, beta-dichloroethyl ether, separating said raffinate fraction fromsaid extract fraction, distilling beta, beta-dichloroethyl ether fromsaid separated raffinate fraction and subje cting .the rafiinate, freedof beta, beta-dichloro ethyl ether, to catalytic cracking.

10. A hydrocarbon conversion process which comprises contacting anaromatic-containing cracking charge hydrocarbon stock having a SayboltUniversal viscosity at 122 F. of about 35 to about 200 seconds and aboiling range of about 350 to about 1000 F. with the extract phaseresulting from previous refining with furfural of a petroleumlubricating oil having a Saybolt Universal viscosity at 210 F. of about35 to about 200 seconds, separating the resulting extract fraction andraflinate fraction, removing furfural from said separated rafiinatefraction, subjecting the furfural-free raffinate fraction to catalyticcracking, recovering gaseous products, gasoline and oil boiling higherthan gasoline and recycling said higher boiling oil to contact with theaforesaid extract phase.

11. A hydrocarbon conversion process which comprises contacting anaromatic-containing cracking charge hydrocarbon stock having a boilingrange of about 350 to about 1000 F. and having a Saybolt Universalviscosity at 122 F. of about 35 to about 200 seconds with the extractphase resulting from previous refining with phenol of a petroleumlubricating oil having a Saybolt Universal viscosity at 210 F. of about35 to about 200 seconds, separating the resulting extract fraction andraffinate fraction, removing phenol from said separated raffinatefraction, subjecting the phenolfree rafi'lnate fraction to catalyticcracking, recovering gaseous products, gasoline and oil boiling higherthan gasoline and recycling said higher boiling oil to contact with theaforesaid extract phase.

12. A hydrocarbon conversion process which comprises contacting anaromatic-containing cracking charge hydrocarbon stock having a SayboltUniversal viscosity at 122 F. of about 35 to about 200 seconds andhaving a boiling range of about 350 to about 1000 F. with .the extractphase resulting from previous refining with beta,

'beta-dichloroethyl ether of a petroleum lubricating oil having aSaybolt Universal viscosity at 210 F. of about 35 to about 200 seconds,separating the resulting extract fraction and raflinate fraction,removing beta,beta-dichloroethyl ether from said separated raffinatefraction, subjecting the beta,beta-dichloroethyl ether-free rafiinatefraction to catalytic cracking, recovering gaseous products, gasolineand oil boiling higher than gasoline and recycling said higher boilingoil to contact with the aforesaid extract phase.

13. An improved process for conversion of a catalytic cracking recyclestock having a Saybolt Universal viscosity at 122 F. of about 35 toabout 200 seconds and a boiling range of about 350 to about 1000 1 whichcornprises contacting the same with the extract phase resulting from therefining with furfural of a petroleum lubricating oil having a SayboltUniversal viscosity at 210 F. of about 35 to about 200 seconds,separating the resulting extract and rafiinate fractions, removingfurfnral from said separated rafiinate fraction and subjecting theresulting raffinate fraction, freed of furfural, to catalytic cracking.

'14. A process for converting hydrocarbons and refining petroleumlubricating oils, which comprises extracting a petroleum lubricating oilhaving a Saybolt Universal viscosity at 210 F. of about 35 to about 200seconds with furfural into an insoluble raifinate fraction and anextract fraction dissolved in furfural, separating said extract fractionfrom said rafiinate fraction, removing furfural from said separatedrafiinate fraction, returning the furfural so removed to further contactwith said lubricating oil, directly contacting said separated extractfraction with an aromatic-containing cracking charge hydrocarbon stockhaving a Saybolt Universal viscosity at 122 F. of about 35 to about 200seconds and a boiling range of about 350 to about 1000 F., separatingthe resulting immiscible extract and rafiinate phases which form,removing furfural from each of said separated phases, returning thefurfural so recovered to further contact with said lubricating oil andsubjecting the raflinate phase, freed of furfural, to catalyticcracking.

15. A process for converting hydrocarbons and refining petroleumlubricating oils, which comprises extracting a petroleum lubricating oilhaving a Saybolt Universal viscosity at 210 F. of about 35 to about 200seconds with phenol into an insoluble raffinate fraction and an extractfraction dissolved in phenol, separating said extract fraction from saidraffinate fraction, removing phenol from said separated raffinatefraction, returning the phenol so removed to further contact with saidlubricating oil, directly contacting said separated extract fractionwith an aromatic-containing cracking charge hydrocarbon stock having aSaybolt Universal viscosity at 122 F. of about 35 to about 200 secondsand a boiling range of 350 to about 1000 F., separating the resultingimmiscible extract and rafiinate phases which form, removing phenol fromeach of said separated phases, returning the phenol so recovered tofurther contact with said lubricating oil and subjecting the ratfinatephase, freed of phenol to catalytic cracking.

16. A process for converting hydrocarbons and refining petroleumlubricating oils, which comprises extracting a petroleum lubricating oilhaving a Saybolt Universal viscosity at 210 F. of about 35 to about 200seconds, with beta,beta-dichloroethyl ether into an insoluble raflinatefraction and an extract fraction dissolved in beta,betadichloroethylether, separating said extract fraction from said raffinate fraction,removing beta,beta-dichloroethyl ether from said separated raflinatefraction, returning the beta,beta-dichloroethyl ether so removed tofurther contact with said lubricating oil, directly contacting saidseparated extract fraction with an aromatic-containing cracking chargehydrocarbon stock having a Saybolt Universal viscosity at 122 F. ofabout 35 to about 200 seconds and having a boiling range of about 350 toabout 1000 F., separating the resulting immiscible extract and rafiinatephases which form, removing beta,beta-dichloroethyl ether from each ofsaid separated phases, returning the beta,beta-dichloroethyl ether sorecovered to further contact with said lubricating oil and subjectingthe raflinate phase, freed of beta,beta-dichloroethyl ether, tocatalytic cracking.

References Cited in the file of this patent UNITED STATES PATENTS2,024,476 Rutherford Dec. 17, 1935 2,139,392 Tijmstra Dec. 6, 19382,201,550 Van Dijck et al May 21, 1940 2,228,510 Dearborn et a1. Jan.14, 1941 2,270,827 Tijmstra Jan. 20, 1942 2,279,550 Benedict et al Apr.14, 1942 2,304,289 Tongberg Dec. 8, 1942 2,342,888 Nysewander et a1 Feb.29, 1944 2,374,102 Jahn et a1. Apr. 17, 1945 FOREIGN PATENTS 441,104Great Britain Jan. 13, 1946

1. A HYDROCARBON CONVERSION PROCESS WHICH COMPRISES CONTACTING ANAROMATIC-CONTAINING CRACKING CHARGE HYDROCARBON STOCK HAVING A SAYBOLTUNIVERSAL VICOSITY AT 122* F. OF ABOUT 35 TO ABOUT 200 SECONDS ANDHAVING A BOILING RANGE OF ABOUT 350* TO ABOUT 1000* F. WITH THE EXTRACTPHASE RESULTING FROM THE REFINING OF A PETROLEUM LUBRICATING OIL HAVINGA SAYBOLT UNIVERSAL VISCOSITY AT 210* F. OF ABOUT 35 TO ABOUT 200SECONDS WITH A SOLVENT SELECTED FROM THE CLASS OF SOLVENTS WHICH HAVE APREFERENTIAL SELECTIVITY FOR THE RELATIVELY MORE AROMATIC TYPECONSTITUENTS AS COMPARED TO THE RELATIVELY MORE PARAFFINIC TYPECONSITUENTS, SEPARATING THE RESULTING EXTRACT AND RAFFINATE FRACTIONS,REMOVING SOLVENT FROM SAID SEPARATED RAFFINATE FRACTION AND SUBJECTINGTHE RESULTING RAFFINATE FRACTION, FREED OF SOLVENT, TO CATALYSTCRACKING.